const assert = require('nanoassert');
const b2wasm = require('@bitgo/blake2b-wasm');

const BYTES_MIN = (module.exports.BYTES_MIN = 16);
const BYTES_MAX = (module.exports.BYTES_MAX = 64);
// eslint-disable-next-line @typescript-eslint/no-unused-vars
const BYTES = (module.exports.BYTES = 32);
const KEYBYTES_MIN = (module.exports.KEYBYTES_MIN = 16);
const KEYBYTES_MAX = (module.exports.KEYBYTES_MAX = 64);
// eslint-disable-next-line @typescript-eslint/no-unused-vars
const KEYBYTES = (module.exports.KEYBYTES = 32);
const SALTBYTES = (module.exports.SALTBYTES = 16);
const PERSONALBYTES = (module.exports.PERSONALBYTES = 16);

// 64-bit unsigned addition
// Sets v[a,a+1] += v[b,b+1]
// v should be a Uint32Array
function ADD64AA(v, a, b) {
  const o0 = v[a] + v[b];
  let o1 = v[a + 1] + v[b + 1];
  if (o0 >= 0x100000000) {
    o1++;
  }
  v[a] = o0;
  v[a + 1] = o1;
}

// 64-bit unsigned addition
// Sets v[a,a+1] += b
// b0 is the low 32 bits of b, b1 represents the high 32 bits
function ADD64AC(v, a, b0, b1) {
  let o0 = v[a] + b0;
  if (b0 < 0) {
    o0 += 0x100000000;
  }
  let o1 = v[a + 1] + b1;
  if (o0 >= 0x100000000) {
    o1++;
  }
  v[a] = o0;
  v[a + 1] = o1;
}

// Little-endian byte access
function B2B_GET32(arr, i) {
  return arr[i] ^ (arr[i + 1] << 8) ^ (arr[i + 2] << 16) ^ (arr[i + 3] << 24);
}

// G Mixing function
// The ROTRs are inlined for speed
function B2B_G(a, b, c, d, ix, iy) {
  const x0 = m[ix];
  const x1 = m[ix + 1];
  const y0 = m[iy];
  const y1 = m[iy + 1];

  ADD64AA(v, a, b); // v[a,a+1] += v[b,b+1] ... in JS we must store a uint64 as two uint32s
  ADD64AC(v, a, x0, x1); // v[a, a+1] += x ... x0 is the low 32 bits of x, x1 is the high 32 bits

  // v[d,d+1] = (v[d,d+1] xor v[a,a+1]) rotated to the right by 32 bits
  let xor0 = v[d] ^ v[a];
  let xor1 = v[d + 1] ^ v[a + 1];
  v[d] = xor1;
  v[d + 1] = xor0;

  ADD64AA(v, c, d);

  // v[b,b+1] = (v[b,b+1] xor v[c,c+1]) rotated right by 24 bits
  xor0 = v[b] ^ v[c];
  xor1 = v[b + 1] ^ v[c + 1];
  v[b] = (xor0 >>> 24) ^ (xor1 << 8);
  v[b + 1] = (xor1 >>> 24) ^ (xor0 << 8);

  ADD64AA(v, a, b);
  ADD64AC(v, a, y0, y1);

  // v[d,d+1] = (v[d,d+1] xor v[a,a+1]) rotated right by 16 bits
  xor0 = v[d] ^ v[a];
  xor1 = v[d + 1] ^ v[a + 1];
  v[d] = (xor0 >>> 16) ^ (xor1 << 16);
  v[d + 1] = (xor1 >>> 16) ^ (xor0 << 16);

  ADD64AA(v, c, d);

  // v[b,b+1] = (v[b,b+1] xor v[c,c+1]) rotated right by 63 bits
  xor0 = v[b] ^ v[c];
  xor1 = v[b + 1] ^ v[c + 1];
  v[b] = (xor1 >>> 31) ^ (xor0 << 1);
  v[b + 1] = (xor0 >>> 31) ^ (xor1 << 1);
}

// Initialization Vector
const BLAKE2B_IV32 = new Uint32Array([
  0xf3bcc908, 0x6a09e667, 0x84caa73b, 0xbb67ae85, 0xfe94f82b, 0x3c6ef372, 0x5f1d36f1, 0xa54ff53a, 0xade682d1,
  0x510e527f, 0x2b3e6c1f, 0x9b05688c, 0xfb41bd6b, 0x1f83d9ab, 0x137e2179, 0x5be0cd19,
]);

const SIGMA8 = [
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3, 11, 8, 12,
  0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4, 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8, 9, 0, 5, 7, 2, 4, 10,
  15, 14, 1, 11, 12, 6, 8, 3, 13, 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9, 12, 5, 1, 15, 14, 13, 4, 10, 0,
  7, 6, 3, 9, 2, 8, 11, 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10, 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7,
  1, 4, 10, 5, 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
  15, 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3,
];

// These are offsets into a uint64 buffer.
// Multiply them all by 2 to make them offsets into a uint32 buffer,
// because this is JavaScript and we don't have uint64s
const SIGMA82 = new Uint8Array(
  SIGMA8.map(function (x) {
    return x * 2;
  })
);

// Compression function. 'last' flag indicates last block.
// Note we're representing 16 uint64s as 32 uint32s
const v = new Uint32Array(32);
const m = new Uint32Array(32);
function blake2bCompress(ctx, last) {
  let i = 0;

  // init work letiables
  for (i = 0; i < 16; i++) {
    v[i] = ctx.h[i];
    v[i + 16] = BLAKE2B_IV32[i];
  }

  // low 64 bits of offset
  v[24] = v[24] ^ ctx.t;
  v[25] = v[25] ^ (ctx.t / 0x100000000);
  // high 64 bits not supported, offset may not be higher than 2**53-1

  // last block flag set ?
  if (last) {
    v[28] = ~v[28];
    v[29] = ~v[29];
  }

  // get little-endian words
  for (i = 0; i < 32; i++) {
    m[i] = B2B_GET32(ctx.b, 4 * i);
  }

  // twelve rounds of mixing
  for (i = 0; i < 12; i++) {
    B2B_G(0, 8, 16, 24, SIGMA82[i * 16 + 0], SIGMA82[i * 16 + 1]);
    B2B_G(2, 10, 18, 26, SIGMA82[i * 16 + 2], SIGMA82[i * 16 + 3]);
    B2B_G(4, 12, 20, 28, SIGMA82[i * 16 + 4], SIGMA82[i * 16 + 5]);
    B2B_G(6, 14, 22, 30, SIGMA82[i * 16 + 6], SIGMA82[i * 16 + 7]);
    B2B_G(0, 10, 20, 30, SIGMA82[i * 16 + 8], SIGMA82[i * 16 + 9]);
    B2B_G(2, 12, 22, 24, SIGMA82[i * 16 + 10], SIGMA82[i * 16 + 11]);
    B2B_G(4, 14, 16, 26, SIGMA82[i * 16 + 12], SIGMA82[i * 16 + 13]);
    B2B_G(6, 8, 18, 28, SIGMA82[i * 16 + 14], SIGMA82[i * 16 + 15]);
  }

  for (i = 0; i < 16; i++) {
    ctx.h[i] = ctx.h[i] ^ v[i] ^ v[i + 16];
  }
}

// reusable parameter_block
const parameter_block = new Uint8Array([
  0,
  0,
  0,
  0, //  0: outlen, keylen, fanout, depth
  0,
  0,
  0,
  0, //  4: leaf length, sequential mode
  0,
  0,
  0,
  0, //  8: node offset
  0,
  0,
  0,
  0, // 12: node offset
  0,
  0,
  0,
  0, // 16: node depth, inner length, rfu
  0,
  0,
  0,
  0, // 20: rfu
  0,
  0,
  0,
  0, // 24: rfu
  0,
  0,
  0,
  0, // 28: rfu
  0,
  0,
  0,
  0, // 32: salt
  0,
  0,
  0,
  0, // 36: salt
  0,
  0,
  0,
  0, // 40: salt
  0,
  0,
  0,
  0, // 44: salt
  0,
  0,
  0,
  0, // 48: personal
  0,
  0,
  0,
  0, // 52: personal
  0,
  0,
  0,
  0, // 56: personal
  0,
  0,
  0,
  0, // 60: personal
]);

// Creates a BLAKE2b hashing context
// Requires an output length between 1 and 64 bytes
// Takes an optional Uint8Array key
function Blake2b(outlen, key, salt, personal) {
  // zero out parameter_block before usage
  parameter_block.fill(0);
  // state, 'param block'

  this.b = new Uint8Array(128);
  this.h = new Uint32Array(16);
  this.t = 0; // input count
  this.c = 0; // pointer within buffer
  this.outlen = outlen; // output length in bytes

  parameter_block[0] = outlen;
  if (key) parameter_block[1] = key.length;
  parameter_block[2] = 1; // fanout
  parameter_block[3] = 1; // depth

  if (salt) parameter_block.set(salt, 32);
  if (personal) parameter_block.set(personal, 48);

  // initialize hash state
  for (let i = 0; i < 16; i++) {
    this.h[i] = BLAKE2B_IV32[i] ^ B2B_GET32(parameter_block, i * 4);
  }

  // key the hash, if applicable
  if (key) {
    blake2bUpdate(this, key);
    // at the end
    this.c = 128;
  }
}

Blake2b.prototype.update = function (input) {
  assert(input instanceof Uint8Array, 'input must be Uint8Array or Buffer');
  blake2bUpdate(this, input);
  return this;
};

Blake2b.prototype.digest = function (out) {
  const buf = !out || out === 'binary' || out === 'hex' ? new Uint8Array(this.outlen) : out;
  assert(buf instanceof Uint8Array, 'out must be "binary", "hex", Uint8Array, or Buffer');
  assert(buf.length >= this.outlen, 'out must have at least outlen bytes of space');
  blake2bFinal(this, buf);
  if (out === 'hex') return hexSlice(buf);
  return buf;
};

Blake2b.prototype.final = Blake2b.prototype.digest;

Blake2b.ready = function (cb) {
  b2wasm.ready(function () {
    cb(); // ignore the error
  });
};

// Updates a BLAKE2b streaming hash
// Requires hash context and Uint8Array (byte array)
function blake2bUpdate(ctx, input) {
  for (let i = 0; i < input.length; i++) {
    if (ctx.c === 128) {
      // buffer full ?
      ctx.t += ctx.c; // add counters
      blake2bCompress(ctx, false); // compress (not last)
      ctx.c = 0; // counter to zero
    }
    ctx.b[ctx.c++] = input[i];
  }
}

// Completes a BLAKE2b streaming hash
// Returns a Uint8Array containing the message digest
function blake2bFinal(ctx, out) {
  ctx.t += ctx.c; // mark last block offset

  while (ctx.c < 128) {
    // fill up with zeros
    ctx.b[ctx.c++] = 0;
  }
  blake2bCompress(ctx, true); // final block flag = 1

  for (let i = 0; i < ctx.outlen; i++) {
    out[i] = ctx.h[i >> 2] >> (8 * (i & 3));
  }
  return out;
}

function hexSlice(buf) {
  let str = '';
  for (let i = 0; i < buf.length; i++) str += toHex(buf[i]);
  return str;
}

function toHex(n) {
  if (n < 16) return '0' + n.toString(16);
  return n.toString(16);
}

const Proto = Blake2b;

module.exports = function createHash(outlen, key, salt, personal, noAssert) {
  if (noAssert !== true) {
    assert(outlen >= BYTES_MIN, 'outlen must be at least ' + BYTES_MIN + ', was given ' + outlen);
    assert(outlen <= BYTES_MAX, 'outlen must be at most ' + BYTES_MAX + ', was given ' + outlen);
    if (key != null) {
      assert(key instanceof Uint8Array, 'key must be Uint8Array or Buffer');
      assert(key.length >= KEYBYTES_MIN, 'key must be at least ' + KEYBYTES_MIN + ', was given ' + key.length);
      assert(key.length <= KEYBYTES_MAX, 'key must be at most ' + KEYBYTES_MAX + ', was given ' + key.length);
    }
    if (salt != null) {
      assert(salt instanceof Uint8Array, 'salt must be Uint8Array or Buffer');
      assert(salt.length === SALTBYTES, 'salt must be exactly ' + SALTBYTES + ', was given ' + salt.length);
    }
    if (personal != null) {
      assert(personal instanceof Uint8Array, 'personal must be Uint8Array or Buffer');
      assert(
        personal.length === PERSONALBYTES,
        'personal must be exactly ' + PERSONALBYTES + ', was given ' + personal.length
      );
    }
  }

  return new Proto(outlen, key, salt, personal);
};

module.exports.ready = function (cb) {
  b2wasm.ready(function () {
    // ignore errors
    cb();
  });
};

module.exports.WASM_SUPPORTED = b2wasm.SUPPORTED;
module.exports.WASM_LOADED = false;

b2wasm.ready(function (err) {
  if (!err) {
    module.exports.WASM_LOADED = true;
    module.exports = b2wasm;
  }
});
